1. Field of the Invention
The present invention relates in general to the field of information handling system cooling fan operations, and more particularly to a system and method for communication with an information handling system cooling fan.
2. Description of the Related Art
As the value and use of information continues to increase, individuals and businesses seek additional ways to process and store information. One option available to users is information handling systems. An information handling system generally processes, compiles, stores, and/or communicates information or data for business, personal, or other purposes thereby allowing users to take advantage of the value of the information. Because technology and information handling needs and requirements vary between different users or applications, information handling systems may also vary regarding what information is handled, how the information is handled, how much information is processed, stored, or communicated, and how quickly and efficiently the information may be processed, stored, or communicated. The variations in information handling systems allow for information handling systems to be general or configured for a specific user or specific use such as financial transaction processing, airline reservations, enterprise data storage, or global communications. In addition, information handling systems may include a variety of hardware and software components that may be configured to process, store, and communicate information and may include one or more computer systems, data storage systems, and networking systems.
With the growing importance of information handling systems to businesses and individuals, reliability has become an increasingly important factor in system design and selection. A growing number of components include monitoring subsystems that monitor for and report abnormal operations so that the risk of overall system failure and down time is decreased. If a failure of a component is detected or anticipated, the component is typically replaced as soon as practicable to avoid unnecessary downtime. Often, relatively inexpensive and non-complex components prove critical to the operation of an information handling system. For example, if one or more cooling fans of an information handling system fail, the system will quickly overheat leading to automated shutdown by safety systems that detect the overheating or, worse, leading to catastrophic failure of one or more components.
Information handling system cooling fans typically run at variable speeds to provide variable amounts of cooling airflow. Running a cooling fan at a reduced speed helps reduce acoustic noise and power consumption where higher speeds are not needed to cool information handling system components. Typically a feedback system is used to control cooling fan speed so that speed increases with operating temperature increases and decreases with operating temperature decreases. One type of cooling fan feedback system works with a three-wire configuration: a power wire, a ground wire and a tachometer wire. The tachometer wire provides fan speed measurements to a system controller located distal the fan. The controller adjusts the fan speed in response to changes in operating temperature by adjusting the power applied to the power wire. Another type of cooling fan feedback system works with a four-wire configuration: a power wire, a ground wire, a tachometer wire and a pulse width modulation (PWM) wire. Instead of controlling fan speed by varying the application of power, four-wire cooling fans send fan speed commands through the PWM wire so that a microcontroller on the cooling fan adjusts fan speed with a constant voltage supply.
A difficulty that sometimes arises with feedback controlled cooling fans is that an incorrect cooling fan model will be inserted into an information handling system to replace a failed cooling fan. If an incorrect cooling fan is inserted, the control of the cooling fan speed may be inaccurate resulting in cooling fan failure or the cooling fan running at too high or too low of a speed. Speeds that are too high create unnecessary acoustic noise and consume excess power while speeds that are too low may result in operating over temperatures and even system shutdown. Typically, in order to avoid installation of an incorrect cooling fan, parts numbers are placed on cooling fans by stickers or the like. However, these stickers may fall off, may be stuck to an incorrect fan type or may be ignored or misread at installation.